There is often found a need to secure articles to and/or hang articles on tubular or rod-like cylindrical objects. The word cylindrical as used here shall be interpreted in its widest meaning, and can be understood to refer to any configuration from triangular, square and pentagonal to a multi-sided, circular-cylindrical, elliptical, pear-shaped or irregular shape. In the case of leisure boats for instance, it is sometimes desired to attach articles to the pulpit of the boat or vessel, or to the guard rail supports or stanchions attached thereto. This applies to both the horizontal and vertical parts of the pulpite and also to other parts thereof. For instance, it is sometimes desired to attach to the pulpit a flag pole holder. Similarly, there is a need in shops which sell wearing apparel to attach elements to tubular stands from which clothes, garments, etc. are normally hung. It is also necessary to be able to connect the tubular members of tubular stands and like structures together when erecting such stands.
To such ends there have been proposed fastener devices which include a conical sleeve or socket which is locked firmly with the aid of conical wedge means. One such device is disclosed in GB 1 241 455. It consists of a conical outer sleeve and an inner sleeve comprising a ring with protruding strip-like axially directed conical wedge means and is intended to be mounted at an arbitrary position on a round shaft. One drawback with fastener devices of this kind is that the sleeve must be fitted from one end of the rod or tubular member, which is not always possible or desirable. In the device of GB 1 241 455 the outer sleeve may have a narrow axial slot, but said outer sleeve is so rigid that it is not possible to widen it so much that it can slip off the shaft side-ways. Furthermore, the wedge means of the inner sleeve exhibit protrusions at their ends such that the outer sleeve can not be removed from the inner sleeve, when the device is mounted an a shaft.
Consequently, in order to enable attachements to be fitted from the side of the rod or tubular member, there have been proposed devices in which a sleeve is provided with an axially extending side opening and a screw for clamping the sleeve in position. One drawback with devices of this kind is that they are unnecessarily bulky and the outwardly projecting screws present obstacles on which things can be caught and snagged. Furthermore, such clamping screws will either afford a poor attachment, with the risk of the sleeve sliding along the rod or tubular member, or will dig into the rod or tubular member and cause indents, scratches and/or outwardly projecting burrs thereon, which cannot always be accepted.
U.S. Pat. No. 2 136 861 describes a fastening device intended to be mounted on the end of a pump-rod for an oil well. It comprises an outer sleeve or body with a tapered bore and a longitudinal slot and a tapered split sleeve with a wedge-shaped rib opposite its slot and an annular groove for a lock ring at its reduced end. The split inner sleeve exhibits a substantially U-shaped opening or slot with a circular bottom portion and tangentially adjoining substantially parallel or slightly diverging sides. The outer sleeve exhibits at its wide end a yoke for connection to a pump jack or similar device. The inner sleeve is obviously made of metal or some other material which is only slightly elastic in order to be able to take up the great forces applied in oil pumping.
For mounting of the device, the inner sleeve is first positioned on the end of a pump rod with an enlargement at said end and then the outer sleeve is laterally adapted to the rod and moved endwise thereof to bring the inner sleeve in seating engagement with the bore, the rib of the inner sleeve being keyed in the slot of the outer sleeve, for example, the slots of the sleeves will be positioned opposite each other. A lock ring is then placed in the groove of the inner sleeve to prevent the two sleeves from moving apart.
The angle of contact between the inner sleeve and the pump rod is only about 180.degree.. Because of this no positive positioning of the rod can be accomplished, but it can be positioned in various inclined or a-tilt positions within the slot or opening of the inner sleeve. Furthermore, in the device of U.S. Pat. No. 2 136 861 the sleeves are not held together by friction forces in mounted position, but the lock ring described above must be used to keep it together. In addition, the device can not be mounted in an arbitrary position on a cylindrical object but only in abutment with a laterally protruding enlargement thereon.
Other examples of areas in which it may be desired to attach articles to rod-like or tubular supports include road work, building work and the winter storage of leisure boats, where it is sometimes desired to attach a tarpaulin to the tubular members of the tarpaulin support frame. At present, the eyelets provided along the sides of the tarpaulin are used to this end. This method, however, leaves large areas of the tarpaulin unsecured and does not enable the tarpaulin to be tensioned satisfactorily, and consequently large surface areas of the tarpaulin are left free to move under the influence of wind. When the wind blows, the tarpaulin will thus bulge inwardly and outwardly within the confines of its attachment points, in other words a given point on the tarpaulin is able to move through some distance before being brought to a halt. The larger the free surface area, the longer the aforesaid distance and the greater the braking force on the tarpaulin, i.e. the higher the stresses generated on the eyelets and the tarpaulin material.
Consequently, constructions have been proposed which lack the provision of eyelets and which enable the tarpaulin to be stretched more rigidly so as to leave much smaller, freely movable surfaces and therewith reduce the wear and tear on the tarpaulin fabric. CH 599 747 teaches an attachment device made of an elastic or resilient material and intended for attaching fabric cloth to a cylindrical rod. This known device comprises two mutually opposing legs and an intermediate web, said legs having a springiness which allows the legs to be forced apart and to spring back when said force is removed. The device is intended to be forced down over a fabric cloth and an underlying rod, so as to peg the cloth to the rod. Located on the web of the device is a ring which facilitates removal of the device and which enables the device to be secured with a cord, for instance on an anchoring element mounted on one end of the rod.
One drawback with this known fastener device is that its fastening ability is limited by the elasticity of the device and the fastener is readily dislodged when subjected to powerful forces, e.g. strong winds. Furthermore, the known fastener device cannot be used to anchor a fabric drape stand with the aid of bracing wires. Such wires have a tendency to pull the fastener devices loose when subjected to tension. The known fastener device is also made of a polymeric material. All polymeric materials tend to age to a greater or lesser extent with time, and will sooner or later lose their mechanical strength, so as to break or loosen under very small tension forces or strain.
It is also known to secure a fabric cloth, by caulking the cloth firmly in a channel or groove with the aid of some suitable matter or elongated rubber strips. An example of this method is found described and illustrated in DE 2 547 599, which teaches a hollow profile of round or triangular cross-section which has an axially extending opening into which two edges of a cloth are intended to be inserted and there caulked securely with the aid of an elastic or resilient member, e.g. a soft rubber profile, such as to produce a joint connection.
One drawback with fastener devices of this kind is that the task of caulking the rubber profile or like means into said channel is both time consuming and difficult to achieve, inter alia because it must be inserted along the whole length of the channel. Removal of the rubber profile or like means from the channel, for the purpose of detaching the fastener device, can also be difficult and may even be hazardous to the cloth. This drawback is particularly manifest when the profile has aged and begun to disintegrate.